Impact-resistant toughened polypropylene and preparation process thereof
By introducing urethane-grafted polypropylene as a compatibilizer and blending it with polyurethane elastomer, the problem of poor impact resistance of polypropylene was solved, achieving an impact-enhancing and toughening effect for polypropylene and improving the mechanical properties of the material.
Patent Information
- Application Number
- CN202511808626.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-03
- Publication Date
- 2026-02-13
AI Technical Summary
Polypropylene materials are prone to brittle fracture when subjected to high-speed impacts, exhibiting poor impact resistance, which limits their application in fields requiring high toughness.
A compatibilizer with urethane groups was prepared by reacting 5-allylresorcinol with isocyanate. This compatibilizer was then grafted onto polypropylene through melt mixing and blended with polyurethane elastomer. By using urethane-grafted polypropylene as a compatibilizer, the compatibility between polypropylene and aromatic polyurethane elastomer was improved, forming a highly efficient compatibilized system.
It significantly improves the notched impact strength and elongation at break of polypropylene, realizing the impact toughening properties of polypropylene. The polyurethane elastomer is uniformly dispersed in the polypropylene matrix, effectively releasing matrix strain and improving the mechanical properties of the material.
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Abstract
Description
TECHNICAL FIELD
[0001] The application relates to the technical field of polypropylene, in particular to an impact-resistant toughened polypropylene and a preparation process. BACKGROUND
[0002] Polypropylene (PP) is a kind of general-purpose plastic with extremely wide application, and has the outstanding advantages of low density, chemical corrosion resistance, easy processing and low cost. However, its molecular structure leads to obvious low-temperature brittleness, that is, poor impact resistance, and especially easy brittle fracture under high-speed impact, which greatly limits its application in fields with high toughness requirements. In order to solve this problem, the blending mode with an elastomer is usually used for toughening modification.
[0003] Polyurethane elastomer (TPU) is a kind of block copolymer composed of soft segments and hard segments, and has excellent high elasticity, wear resistance, oil resistance and amazing toughness due to its unique micro-phase separation structure, and is an ideal high molecular toughening agent. Theoretically, the perfect complementation can be realized by blending TPU with PP, and a material with both rigidity and toughness can be prepared. However, the molecular chain of TPU contains strong polar groups, and there is essential "thermodynamic incompatibility" between the non-polar PP, if the two are directly blended, the interfacial bonding force between the two is weak, which can lead to serious phase separation, and the stress cannot be effectively transferred, and the performance of the composite material is deteriorated.
[0004] The compatibilizer is a kind of key additive for polymer blending, and its essence is a kind of "interfacial bridging agent". When two incompatible polymers (such as polar and non-polar) are blended, the compatibilizer is preferentially distributed in the interfacial region of the two phases through the different segments in its molecular structure which have good affinity with the two polymers respectively. The interfacial tension is reduced: the two originally incompatible polymers can be more detailed and uniformly dispersed. The compatibilizer strengthens the adhesion between the two phases through intermolecular entanglement or chemical reaction, enhances the interfacial bonding, forms a firm interfacial layer, realizes the effective stress transfer between the two phases, and significantly improves the compatibility, phase morphology and final mechanical properties of the blended material. SUMMARY
[0005] (I) Technical problems solved:
[0006] In view of the defects of the prior art, the application provides an impact-resistant toughened polypropylene and a preparation process, and solves the problems of poor impact resistance and toughness of polypropylene.
[0007] (II) Technical scheme:
[0008] A preparation process of an impact-resistant toughened polypropylene, and a preparation method of the impact-resistant toughened polypropylene is as follows:
[0009] Step (1), nitrogen is introduced into a flask equipped with a condenser reflux device, 5-allyl resorcinol, isocyanate, 1,4-dioxane, dibutyltin dilaurate in a ratio of 100g:(86-137)g:(400-500)mL:(0.8-1.5)g are added, heated to 40-70℃, stirred for 2-3h, rotary evaporation, the crude product is recrystallized in ethanol to obtain 5-allyl resorcinol diurethanes, and the preparation reaction formula is:
[0010]
[0011] Step (2), polypropylene, 5-allyl resorcinol diurethanes and dicumyl peroxide in a ratio of 100g:(3-15)g:(0.2-0.8)g are uniformly mixed, and placed in a torque rheometer to melt and mix for grafting to obtain a crude product; the crude product is heated and dissolved in xylene, acetone is added, filtered, and the precipitate is extracted with acetone in a Soxhlet extractor for 24-48h to obtain urethane grafted polypropylene.
[0012] Step (3), polypropylene, polyurethane elastomer, urethane grafted polypropylene and antioxidant in a ratio of 100g:(5-20)g:(1.5-6)g:(0.1-0.3)g are uniformly mixed, and extruded through a twin-screw extruder to obtain impact toughened polypropylene.
[0013] Further, the molecular formula of the isocyanate in step (1) is NCO-C n H 2n+1 , and n is 2-8.
[0014] Further, the temperature of the melt mixing in step (2) is 175-190℃, and the grafting time is 10-20min.
[0015] Further, the temperature of the 1-5 zones of the twin-screw extruder in step (3) is 120-200℃, and the rotation speed is 60-120r / min.
[0016] (Three) beneficial technical effects:
[0017] The present application reacts the phenolic hydroxyl group of 5-allyl resorcinol with the isocyanate group of isocyanate to prepare 5-allyl resorcinol diurethanes containing urethane groups, then grafts polypropylene on 5-allyl resorcinol diurethanes through melt mixing to prepare the compatibilizer urethane grafted polypropylene of polypropylene and aromatic polyurethane elastomer. Finally, the uniform mixture of polypropylene, aromatic polyurethane elastomer and the compatibilizer is extruded through a twin-screw machine to obtain impact toughened polypropylene.
[0018] The application utilizes urethane grafted polypropylene as a compatibilizer, which is blended with polypropylene and aromatic polyurethane elastomer, so as to improve the notched impact strength and elongation at break of polypropylene, and realize the impact toughening performance of polypropylene. The multiple urethane groups contained in the molecular chain of the compatibilizer have good compatibility with the polyurethane elastomer, and meanwhile, the benzene ring structure is introduced into the compatibilizer, so as to further improve the compatibility between the aromatic polyurethane containing the benzene ring structure and polypropylene. By means of the good interfacial bonding between the grafted polypropylene segment and the polypropylene matrix, the high-efficiency compatibilization between the two phases is realized, the blending system with suitable phase domain size and strong interfacial bonding force is obtained, the polyurethane elastomer is uniformly dispersed in the polypropylene matrix, the cavitation of the polyurethane elastomer occurs under stress, the yield stress of polypropylene is effectively reduced, and the shear yield of the matrix is promoted, so as to significantly improve the mechanical properties such as notched impact strength of the material. DETAILED DESCRIPTION
[0019] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with examples. It should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the present application.
[0020] 5-allylresorcinol is prepared according to the method of the literature "Antiprotozoal and antimicrobial activities of O-alkylated and formylated acylphloroglucinols." in the journal "Bioorganic & Medicinal Chemistry", 2007, 15: 87-96. The structural formula is
[0021] The following polyurethane elastomer is an aromatic polyurethane elastomer, the model number is TPU American Lubrizol 58123, and is purchased from Dongguan Jiapan Plastic Raw Material Co., Ltd.
[0022] Example 1:
[0023] Step (1), nitrogen is introduced into a flask equipped with a condenser reflux device, 8 g (48.18 mmol) of 5-allylresorcinol, 6.9 g of isocyanate ethyl, 40 mL of 1,4-dioxane, 0.08 g of dibutyltin dilaurate are added, heated to 60 DEG C, stirred for 3 h, rotary evaporation, the crude product is recrystallized in ethanol, and 5-allylresorcinol is obtained.
[0024] Step (2), 50 g of polypropylene, 1.5 g (4.87 mmol) of 5-allyl-m- diaminoformyl benzene and 0.2 g of dicumyl peroxide were mixed uniformly, placed in a torque rheometer, and melt-kneaded for grafting reaction at 180℃ for 15 min to obtain a crude product; the crude product was heated and dissolved in xylene, 500 mL of acetone was added, filtered, and the precipitate was extracted with acetone in a Soxhlet extractor for 48 h to obtain the urethane-grafted polypropylene.
[0025] Step (3), 1000 g of polypropylene, 50 g of polyurethane elastomer, 15 g of urethane-grafted polypropylene, and 2 g of antioxidant 1010 were mixed uniformly, extruded through a twin-screw extruder, the temperature of each section of the screw extruder was 120℃, 150℃, 180℃, 200℃, and 190℃, the rotation speed was 100 r / min, and granulation was performed to obtain the impact-toughened polypropylene.
[0026] Example 2:
[0027] Step (1), a flask equipped with a condenser reflux device was purged with nitrogen, 8 g of 5-allyl-m-dihydroxybenzene, 11 g of pentyl isocyanate, 30 mL of 1,4-dioxane, and 0.12 g of dibutyltin dilaurate were added, heated to 70℃, stirred for 2 h, rotary evaporated, and the crude product was recrystallized in ethanol to obtain 5-allyl-m-diaminoformyl benzene.
[0028] Step (2), 50 g of polypropylene, 3 g of 5-allyl-m-diaminoformyl benzene, and 0.1 g of dicumyl peroxide were mixed uniformly, placed in a torque rheometer, and melt-kneaded for grafting reaction at 190℃ for 10 min to obtain a crude product; the crude product was heated and dissolved in xylene, 500 mL of acetone was added, filtered, and the precipitate was extracted with acetone in a Soxhlet extractor for 24 h to obtain the urethane-grafted polypropylene.
[0029] Step (3), 1000 g of polypropylene, 85 g of polyurethane elastomer, 26 g of urethane-grafted polypropylene, and 1 g of antioxidant 1010 were mixed uniformly, extruded through a twin-screw extruder, the temperature of each section of the screw extruder was 120℃, 150℃, 180℃, 200℃, and 190℃, the rotation speed was 80 r / min, and granulation was performed to obtain the impact-toughened polypropylene.
[0030] Example 3:
[0031] Step (1), a flask equipped with a condenser reflux device was purged with nitrogen, 8 g of 5-allyl-m-dihydroxybenzene, 9 g of n-butyl isocyanate, 40 mL of 1,4-dioxane, and 0.06 g of dibutyltin dilaurate were added, heated to 40℃, stirred for 3 h, rotary evaporated, and the crude product was recrystallized in ethanol to obtain 5-allyl-m-diaminoformyl benzene.
[0032] Step (2), 50 g of polypropylene, 4.5 g of 5-allyl-m-xylylene diurethane and 0.3 g of dicumyl peroxide were mixed uniformly, and placed in a torque rheometer, and melt-kneaded grafting reaction was carried out at 175°C for 15 min to obtain a crude product; the crude product was heated and dissolved in xylene, 500 mL of acetone was added, filtered, and the precipitate was extracted with acetone in a Soxhlet extractor for 36 h to obtain urethane grafted polypropylene.
[0033] Step (3), 1000 g of polypropylene, 125 g of polyurethane elastomer, 37 g of urethane grafted polypropylene, and 3 g of antioxidant 1010 were mixed uniformly, and extruded through a twin-screw extruder, the temperature of each section of the screw extruder was 120°C, 150°C, 180°C, 200°C, and 190°C, the rotation speed was 60 r / min, and granulation was carried out to obtain impact-resistant toughened polypropylene.
[0034] Example 4:
[0035] Step (1), 50 g of polypropylene, 6 g of 5-allyl-m-xylylene diurethane (obtained by the preparation method of Example 1) and 0.4 g of dicumyl peroxide were mixed uniformly, and placed in a torque rheometer, and melt-kneaded grafting reaction was carried out at 180°C for 20 min to obtain a crude product; the crude product was heated and dissolved in xylene, 500 mL of acetone was added, filtered, and the precipitate was extracted with acetone in a Soxhlet extractor for 36 h to obtain urethane grafted polypropylene.
[0036] Step (2), 1000 g of polypropylene, 160 g of polyurethane elastomer, 48 g of urethane grafted polypropylene, and 1 g of antioxidant 1010 were mixed uniformly, and extruded through a twin-screw extruder, the temperature of each section of the screw extruder was 120°C, 150°C, 180°C, 200°C, and 190°C, the rotation speed was 120 r / min, and granulation was carried out to obtain impact-resistant toughened polypropylene.
[0037] Example 5:
[0038] Step (1), 50 g of polypropylene, 7.5 g of 5-allyl-m-xylylene diurethane (obtained by the preparation method of Example 1) and 0.2 g of dicumyl peroxide were mixed uniformly, and placed in a torque rheometer, and melt-kneaded grafting reaction was carried out at 190°C for 10 min to obtain a crude product; the crude product was heated and dissolved in xylene, 500 mL of acetone was added, filtered, and the precipitate was extracted with acetone in a Soxhlet extractor for 48 h to obtain urethane grafted polypropylene.
[0039] Step (2), 1000 g of polypropylene, 200 g of polyurethane elastomer, 60 g of urethane grafted polypropylene, 2 g of antioxidant 1010 were mixed uniformly, extruded through a twin-screw extruder, the temperature of each section of the screw extruder was 120℃, 150℃, 180℃, 200℃, 190℃, the rotating speed was 100 r / min, and granulation was performed to obtain the impact toughened polypropylene.
[0040] Comparative Example 1: The difference from Example 1 is that no urethane grafted polypropylene is added.
[0041] Step (1), 1000 g of polypropylene, 50 g of polyurethane elastomer, 2 g of antioxidant 1010 were mixed uniformly, extruded through a twin-screw extruder, the temperature of each section of the screw extruder was 120℃, 150℃, 180℃, 200℃, 190℃, the rotating speed was 100 r / min, and granulation was performed to obtain the modified polypropylene.
[0042] Comparative Example 2: The difference from Example 1 is that hydroxyethyl acrylate is used to replace 5-allyl resorcinol.
[0043] Step (1), a flask equipped with a condenser reflux device was purged with nitrogen, 5.6 g (48.18 mmol) of hydroxyethyl acrylate, 6.9 g of ethyl isocyanate, 40 mL of 1,4-dioxane, 0.08 g of dibutyltin dilaurate were added, heated to 60℃, stirred for 3 h, rotary evaporation, the crude product was recrystallized in ethanol to obtain ethyl carbamate acrylate. The structural formula is:
[0044] Step (2), 50 g of polypropylene, 0.92 g (4.87 mmol) of ethyl carbamate acrylate and 0.2 g of dicumyl peroxide were mixed uniformly, placed in a torque rheometer, and melt mixed for grafting reaction at 180℃ for 15 min to obtain a crude product; the crude product was heated and dissolved in xylene, 500 mL of acetone was added, filtered, and the precipitate was extracted with acetone in a Soxhlet extractor for 48 h to obtain ethyl carbamate acrylate grafted polypropylene.
[0045] Step (3), 1000 g of polypropylene, 50 g of polyurethane elastomer, 15 g of ethyl carbamate acrylate grafted polypropylene, 2 g of antioxidant 1010 were mixed uniformly, extruded through a twin-screw extruder, the temperature of each section of the screw extruder was 120℃, 150℃, 180℃, 200℃, 190℃, the rotating speed was 100 r / min, and granulation was performed to obtain the polypropylene.
[0046] Comparative Example 3: The difference from Example 1 is that 4-hydroxystyrene is used to replace 5-allyl resorcinol.
[0047] Step (1), a flask equipped with a condenser reflux device was purged with nitrogen, 5.8 g (48.18 mmol) of 4-hydroxystyrene, 6.9 g of ethyl isocyanate, 40 mL of 1,4-dioxane, 0.08 g of dibutyltin dilaurate were added, heated to 60°C, stirred for 3 h, rotary evaporation, the crude product was recrystallized in ethanol to obtain 4-(carbamate ethyl) styrene. The structural formula is:
[0048] Step (2), 50 g of polypropylene, 0.93 g (4.87 mmol) of 4-(carbamate ethyl) styrene and 0.2 g of dicumyl peroxide were mixed uniformly, placed in a torque rheometer, melt mixed and grafted at 180°C for 15 min to obtain a crude product; the crude product was heated and dissolved in xylene, 500 mL of acetone was added, filtered, the precipitate was extracted with acetone in a Soxhlet extractor for 48 h to obtain 4-(carbamate ethyl) styrene grafted polypropylene.
[0049] Step (3), 1000 g of polypropylene, 50 g of polyurethane elastomer, 15 g of 4-(carbamate ethyl) styrene grafted polypropylene, and 2 g of antioxidant 1010 were mixed uniformly, extruded through a twin-screw extruder, the temperature of each section of the screw extruder was 120°C, 150°C, 180°C, 200°C, and 190°C, the rotation speed was 100 r / min, and the pellets were obtained to obtain an impact toughened polypropylene.
[0050] The notched impact strength of the polypropylene was tested according to the method of GB / T 1043.1-2008, the number of test samples in each group was not less than 5, and the average value of 5 measurements was taken.
[0051] The flexural strength of the polypropylene was tested according to the method of GB / T 9341-2008, the number of test samples in each group was not less than 5, and the average value of 5 measurements was taken.
[0052] The tensile strength and elongation at break of the polypropylene were tested according to the method of GB / T 1040.1-2018, the number of test samples in each group was not less than 5, and the average value of 5 measurements was taken.
[0053] Table 1 Performance test of polypropylene
[0054]
[0055] Compared with Comparative Example 1, Examples 1-5 use urethane grafted polypropylene as a compatibilizer, which is blended with polypropylene and aromatic polyurethane elastomer, to improve the notched impact strength and elongation at break of polypropylene, and achieve the impact toughening performance of polypropylene. The multiple urethane groups contained in the molecular chain of the compatibilizer have good compatibility with the polyurethane elastomer, and the introduction of benzene ring structure in the compatibilizer further improves the compatibility between the aromatic polyurethane containing benzene ring structure and polypropylene. With the help of the good interfacial bonding between the grafted polypropylene segment and the polypropylene matrix, efficient compatibilization between the two phases is achieved, and a blending system with suitable domain size and strong interfacial bonding force is obtained, so that the polyurethane elastomer is uniformly dispersed in the polypropylene matrix, and cavitation occurs under stress, effectively releasing the strain of the matrix, reducing the yield stress of polypropylene, and promoting the shear yielding of the matrix, thereby significantly improving the mechanical properties such as notched impact strength of the material.
[0056] Comparative Example 1 is polypropylene without adding compatibilizer urethane grafted polypropylene, and the polyurethane elastomer particles cannot be well dispersed in the polypropylene matrix, and cannot release the strain of the matrix through cavitation, reduce the yield stress of polypropylene, so the notched impact strength is low, and the impact toughening effect cannot be achieved.
[0057] Comparative Example 2 uses acrylate urethane grafted polypropylene as a compatibilizer, which does not contain benzene ring structure and has fewer urethane groups, and the effect of compatibilizing polypropylene and aromatic polyurethane elastomer is poor, the toughening effect of polyurethane elastomer is poor, and the impact strength and other properties of polypropylene material are low.
[0058] Comparative Example 3 uses 4-(urethane) styrene grafted polypropylene as a compatibilizer, which has fewer urethane groups, and the effect of compatibilizing polypropylene and aromatic polyurethane elastomer is poor, the toughening effect of polyurethane elastomer is poor, and the impact strength and other properties of polypropylene material are low.
[0059] The above only describes the preferred embodiments of the present application, but the present application is not limited to the embodiments shown, and any changes or modifications made in accordance with the concept of the present application, or equivalent embodiments with equivalent changes, are still within the scope of the present application.
Claims
1. A preparation process for impact-resistant and toughened polypropylene, characterized in that, The method for preparing the impact-resistant and toughened polypropylene is as follows: Step (1): Nitrogen gas is introduced into a flask equipped with a reflux condenser, and 5-allyl resorcinol, isocyanate, 1,4-dioxane, and dibutyltin dilaurate are added. The mixture is heated to carry out the reaction, and then rotary evaporated. The crude product is recrystallized in ethanol to obtain 5-allyl m-dicarbamate benzene. Step (2): Mix polypropylene, 5-allyl-m-dicarbamate benzene and dicumyl peroxide evenly, place in a torque rheometer, melt-mix and graft to obtain crude product; heat the crude product to dissolve in xylene, add acetone, filter, and extract the precipitate in a Soxhlet extractor with acetone for 24-48 hours to obtain carbamate-grafted polypropylene. Step (3): Mix polypropylene, polyurethane elastomer, urethane-grafted polypropylene and antioxidant evenly, extrude through a twin-screw extruder, and granulate to obtain impact-resistant toughened polypropylene.
2. The preparation process of impact-resistant toughened polypropylene according to claim 1, characterized in that, The ratio of 5-allyl resorcinol, isocyanate, 1,4-dioxane, and dibutyltin dilaurate is 100g:(86-137)g:(400-500)mL:(0.8-1.5)g.
3. The preparation process of impact-resistant toughened polypropylene according to claim 1, characterized in that, The ratio of polypropylene, 5-allyl-m-dicarbamate benzene, and dicumyl peroxide is 100g:(3-15)g:(0.2-0.8)g.
4. The preparation process of impact-resistant toughened polypropylene according to claim 1, characterized in that, The ratio of polypropylene, polyurethane elastomer, urethane-grafted polypropylene and antioxidant is 100g:(5-20)g:(1.5-6)g:(0.1-0.3)g.
5. The preparation process of impact-resistant toughened polypropylene according to claim 1, characterized in that, The isocyanate in step (1) has the molecular formula NCO-CnH2n+1, where n is 2-8.
6. The preparation process of impact-resistant toughened polypropylene according to claim 1, characterized in that, The heating temperature in step (1) is 40-70℃, and the reaction time is 2-3h.
7. The preparation process of impact-resistant toughened polypropylene according to claim 1, characterized in that, The temperature for melting and mixing in step (2) is 175-190℃, and the grafting time is 10-20 min.
8. The preparation process of impact-resistant toughened polypropylene according to claim 1, characterized in that, In step (3), the temperature of zones 1-5 of the twin-screw extruder is 120-200℃, and the rotation speed is 60-120r / min.
9. An impact-resistant toughened polypropylene obtained by the preparation process according to any one of claims 1-8.